That's part of your problem. You said you cleaned the screens in the tank and put them back in. Most folks do the Hutch and Harpoon Mod, which is get rid of the screens, install a new intake tube, divert the return line, and install a pre-filter between the tank and the fuel pump. Not saying that the screens may still be an issue. It's just that by doing what others have done, eliminates them from ever being a problem again.

 

 

 

 

If you prime the fuel system engine off and hear the fuel bowl whining the fuel pressure regulator spring is weak. My truck was just getting no boost because the wastegatebsolenoid was broken with no codes just reduced performance. In the radio on position It was cycling was my discovery. Once I put a new one one in 2 minutes my truck had instant power and RPMs to get me going dropped by a lot. If you have never replaced the spring and had the truck a long time replace it anyways. It’s cheap to do it your self project with a quick install plus keeps the injectors well fed and long lasting.

 

 

How can you tell by looking at them, what do you see?

 

What he said.

 

 

 

OK. So, did the mechanic address the "LOW" fuel pressure? 40 psi is low. If not, you'll probably be purchasing injectors again sooner rather than later. All of my 7.3's run between 65-68 psi for fuel pressure at idle. The '99 which has 175/80's is set to 68 psi and will drop to about 55 on a WOT run and will drop to about 60 psi while towing 16k up a mountain pass. If yours drops the same amount you'll be in the high 20's which can potentially damage your injectors.

I am almost certain that it is the fuel pump starting to die since I have eliminated all other potential choke points on the '99 with the H&H, Racor PS-120, and regulated return. I have a fuel pump on order.

The H&H is highly recommended to save your injectors from the lack of lubrication that occurs when there is air in the fuel. If that has not been done to your truck, then I will guarantee that there is air in the fuel. The H&H eliminates air for a reasonable price, about $45 and about 2 hours of your time. Low fuel pressure can also cause a lack of lubrication and a lack of cooling at the nozzles.

http://www.riffraffdiesel.com/riffra...-fuel-mod-kit/

The fuel pressure spring upgrade mentioned earlier would also be cheap insurance especially since you are pushing more fuel through the system with the 175's.

http://www.riffraffdiesel.com/upgrad...ing-kit-99-03/

As stated earlier, consider purchasing and installing a fuel pressure gauge and EGT gauge especially now that you are running 175/146 which I think = 175/0's or stock nozzles. You don't want to cook your engine or those new injectors. Swamps builds decent injectors but most of us would have suggested a better performing, cooler running, higher HP and torque capable injector which could also be tuned very close to stock levels.

If the two issues above have not been addressed then the additional fuel could mask the original problem and "if" it is masking it, they are also exacerbating the original problem.

I have two friends that run Swamps tunes with the same injectors that you have. After reading about your experience, I'lll bet the tunes are almost identical. 4 out of 5 of those tunes shift kinda harsh and only one of those tunes keep EGT's in check. They also don't reside within the same tune so they never get the best of both worlds in the same tune. This is after several revisions. The remainder of the tunes cause low ICP followed by ICP spikes at throttle lift which generally means there is a long FIPW in play and high EGT's accompany that most times. The tunes are OK meaning that there are better tunes on the market unless you go to Swamps and get LIVE tuning done. My cousin is running 1023 Diesel tunes and they are a HUGE improvement over Swamps and DP for both shifting and EGT's and the tunes were emailed.

I hope this was helpful and what you were looking for.

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Swamps sells a real good transmission for our trucks! And their tunes work well with them.